AUSTIN, TEXAS - Arturo Alviter Balderrama lost his focus, his grade point average and eventually his freedom. But his troubles had deeper roots.

"At 13, I found myself using low-level drugs for fun," Arturo, 17, told a legislative committee last month. "After about a year I had moved on to more serious drugs and found myself running with the wrong crowd."

In Texas, lawmakers are at the center of a national movement to reform the discipline system known as the school-to-prison pipeline. The cause has drawn bipartisan support with tales of citations issued for truancy, gum-chewing and possession of scissors. The proposed reforms focus on removing criminal sanctions for youthful behavior.

For kids like Arturo, though, mental health plays a complex, important and largely overlooked role in the struggle to emerge from adolescence on a solid path. Following his brother's example, Arturo said, he slipped into serious drug abuse. Before reaching 10th grade this year at Del Valle High School, he spent nearly a year in jail or on probation for burglary.

Among the 1,411 inmates in the custody of the Texas Juvenile Justice Department, rates of diagnosed mental illness now exceed rates of gang membership, according to records obtained by The Associated Press through the state's open records law. Nearly 1,100 cases involve substance abuse or dependence.

Aside from that broad category, the most prevalent single diagnosis is conduct disorder, with 770 cases.

The agency declined to specify how many diagnoses overlap. But experts say the numbers underscore a problem beyond the criminalization of horseplay.

"So many instances of misbehavior in the schools are examples of kids with diagnosed or undiagnosed forms of mental illness," said Michele Deitch, a senior lecturer on criminal justice policy at the University of Texas. "The misbehavior is oftentimes a symptom of the mental illness."

Nationally, the campaign to reform school discipline has united such disparate groups as the American Civil Liberties Union and the conservative Americans for Tax Reform. It gained momentum from a landmark 2011 study by the Council of State Governments.

The study, "Breaking Schools' Rules," focused on a million public school students in Texas, finding that a majority had been suspended or expelled at some point. Black students and students with disabilities were more likely to be removed from the classroom. And students who were expelled were more likely to end up in the criminal justice system, the study found.

While civil rights groups focused on the inequity, conservatives cast the issue as a matter of fiscal responsibility.

"Misbehavior that leads to disruption in the classroom does not warrant a $500 Class C misdemeanor ticket and subsequent trip to municipal court," the conservative power broker Grover Norquist wrote in a letter to the Texas Legislature last week. "An after-school detention or two, for example, should do the trick just fine, without great cost to taxpayers or overburdening our courts."

The state education commissioner, Michael Williams, has expressed support for the cause, seeking more authority to intervene in districts with high rates of suspensions and expulsions.

Much of the proposed legislation has derived from recommendations by the Texas Judicial Council, which sets policy for the state's courts. Criminal justice reformers are tracking 18 different proposals to decriminalize classroom offenses, plus others that would address fines, record-keeping, pretrial detention periods and deferral of prosecution.

Sen. John Whitmire, chairman of the Committee on Criminal Justice, has filed a bill that would replace criminal penalties for truancy with progressive sanctions including warning letters, behavior contracts and school-based community service.

"We should fix the root cause of truancy," Whitmire said, "and not require students and parents to show up in court, where they are often times required to pay fines of $500 and court costs of $85 which does not solve the problem, and in some cases if the fine is not paid, leads to arrest."

"We want the students to be successful," said Archie McAfee, executive director of the Texas Association of Secondary School Principals. "Sometimes students have to be put in situations where they know there's a penalty if they miss school."

But those who work closely with young offenders say the decriminalization movement fails to account for the full scope of the problem. In the confusion of adolescence, they say, signs of mental illness are easily overlooked or misinterpreted, even by well-intentioned parents and teachers.

"Substance abuse is a huge factor," said Tricia Anglea, a UT researcher who works with teenage offenders at the Travis County Correctional Facility. "The problem is that in those beginning phases we are being punitive as opposed to being therapeutic. It's really difficult when a child is sitting in front of you and swearing and cussing at you to remember that this is a child."

For Arturo, who visited the Capitol to testify for a measure requiring juvenile probation departments to refer young offenders with signs of chemical dependency to treatment, a counseling program has helped. He said he is passing all his classes, working at a boxing gym and spending his free time remodeling bicycles.

"I didn't get drug classes until probation," he said, "but I know it was those classes that helped me see when I was starting to slip again and ask for help."